This competing continuation application examines a developmental model of adolescents'peer and family experiences as predictors of long-term psychosocial outcomes in adulthood. We propose to follow a diverse community sample of 172 adolescents, their parents, peers, and romantic partners from ages 13 to 27. We focus upon two stage-salient tasks of adolescence establishing autonomy and maintaining and building social bonds and hypothesize that the resolution of these tasks will be fundamental to understanding qualities of adult psychosocial functioning. We also assess important cognitive, affective, and contextual factors that may mediate continuities and discontinuities from adolescent to adult relationship quality and that may potentially serve as targets for intervention efforts. We organize our efforts into three primary Aims: Aim 1: Parent and Peer Predictors of Adult Relationship Quality: We begin by seeking to identify critical continuities in adolescent relationship qualities that persist into early adulthood. We focus upon predictors of aspects of adult relationships particularly social isolation and hostility known to be closely linked to both mental and physical health. Aim 2: Mediators &Moderators of Continuities and Discontinuities from Adolescence to Adulthood: We next examine several processes that potentially mediate the continuities or account for the discontinuities identified in Aim 1. We focus on three specific factors: the individual's attachment organization, rejection sensitivity, and major developmental/contextual transitions. Aim 3: Early Adult Adaptational Outcomes: Direct &Mediated Pathways from Adolescence: Finally, we consider adolescent-era predictors of internalizing and externalizing symptoms in adulthood and of the development of functional autonomy the capacity to manage one's own career, financial, and residential needs. We assess both direct predictions from adolescent relationship qualities across this fifteen-year span, as well as predictions mediated via adult relationship qualities (Aim 1) and intervening factors (Aim 2). This study builds on the vast body of research that has examined relational predictors of functioning within adolescence but now seeks to extend and ground this research by determining which of the many qualities of social relationships that have been identified as important within adolescence are actually predictive of long-term, life outcomes in adulthood. As such, it seeks to inform: a) parents, educators, and clinicians working with adolescents and early adults;b) interventions targeting parenting behaviors and/or peer influences (e.g., delinquency, aggression, and substance abuse prevention and treatment programs);and c) developing theories of the links between social relationships and functional outcomes across this critical portion of the lifespan. PUBLIC HEALTH RELEVANCE: This study seeks to identify essential qualities of adolescents'relationships with peers and parents that predict long-term success or failure in adult psychological functioning. It is designed to provide knowledge that will ultimately reduce the incidence of both externalizing symptoms (e.g., delinquency, aggression, substance abuse) and internalizing symptoms (e.g., depression, anxiety, social isolation) in late adolescence and early adulthood by informing: a) parents, educators, and clinicians working with adolescents and early adults;b) interventions targeting parenting behaviors and/or peer influences (e.g., delinquency, aggression, and substance abuse prevention and treatment programs);and c) developing theories of the links between social relationships and functional outcomes across this critical portion of the lifespan.